Design vs Testing · both proven

frontend-design vs writing-guidelines

Both skills were run through Claude twice: once on a fixed brief without the skill, once with it. The briefs differ because each is written for the job the skill claims to do, so compare each skill against its own baseline, then decide which difference matters for your work. They are in different categories, so this is a choice of job, not a head-to-head on the same job.

frontend-design

Guidance for distinctive, intentional visual design when building new UI or reshaping an existing one. Helps with aesthetic direction, typography, and making choices that don't read as templated defaults.

Category: Design
Source: anthropics/skills
License: Not stated
Proof model: claude-opus-5-5
Brief: “Build the marketing landing page for Halcyon, a calm AI calendar app for busy founders. Include a hero with a product mockup of the app, a short row of customer logos, three feature sections that each show the product, a customer quote, a pricing teaser, and a footer. Draw any illustrations or product shots with inline SVG and CSS.”
Skill commit: dbd4588

Without the skillWith frontend-design

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Without, runWith frontend-design, run3 independent runs per side, none selected by hand.

Download the with-skill page

writing-guidelines

Review docs/prose for Writing Guidelines compliance. Use when asked to "review my docs", "check writing style", "audit prose", "review docs voice and tone", or "check this page against the writing handbook".

Category: Testing
Source: vercel-labs/agent-skills
License: Not stated
Proof model: claude-opus-5-5
Brief: “Review and rewrite this getting-started page for Pipewell, a data pipeline CLI. The draft opens with two paragraphs of company history, mixes 'you' and 'the user', buries the install command in the fourth paragraph, uses passive voice throughout, and ends without a next step. Write the improved page as a single HTML document, followed by a short list of what you changed and why.”
Skill commit: 063bee9

Without the skillWith writing-guidelines

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Without, runWith writing-guidelines, run3 independent runs per side, none selected by hand.

Download the with-skill page

We don’t pick a winner for you: the pages are the evidence. Both proofs can be repeated with the brief, model and commit shown above. See alternatives to frontend-design or alternatives to writing-guidelines.